As a result of improvements in technology, some telescope manufacturers have been working on devices for assisting amateur sky watchers in finding specific stars, groups of stars or other celestial objects. Some of these devices suffer from one or more complexities or high cost that limit their widespread use by the public. For example, U.S. Pat. No. 6,392,799 which is implemented in commercially available computerized telescopes, discloses a system for aligning a telescope which requires that the user first enter his location, the date and the time of use (including figuring out if he is in daylight savings time or not, which few users care to commit to memory), then mechanically rotate the scope to a home position relative to its drive motors to set the starting point for its encoders, and then requires the user to pick up the scope and point it north, very few people can accurately point to magnetic north, even using a compass, and fewer still can distinguish between magnetic north and true north, and then requires that the user level the telescope and tell the system that the scope is aligned, whereupon the telescope will slew to an expected altitude-azimuth position of a bright star such a Vega, Arcturus, Sirius, etc., whereupon the user is instructed to adjust the scope with fine slewing adjustments to center the bright star in the field of view and tell the scope that the bright star is centered in the field of view, whereupon the telescope slews to the vicinity of a second bright star and the system again instructs the user is instructed to adjust the scope with fine slewing adjustments to center the bright star in the field of view and tell the scope that the bright star is centered in the field of view, whereupon the alignment often fails and the user must restart the procedure from scratch. Beside the labor of this procedure, its success depends on perfect initial rotation to home, accurate leveling and orienting to north, and accurate entry of time, date and location. If the user is just a few degrees off on any of these steps, or a few minutes off on the time, or a short distance off on location, the scope will slew to the alignment stars but will be a few degrees off. The alignment stars will probably not appear in the spotting scope, and definitely will not appear in the main scope. A novice user has no hope of aligning the scope, and must learn the names of several prominent stars that the system is likely to use (Vega, Arcturus, Spica, for example, if it is summer), then center the telescope's spotting scope on the prominent star, in which case the user must know the position of the prominent star amongst its immediate neighbors visible in the spotting scope, and then seek to center the prominent star in the small (about 1° for a low magnification 25 mm plossi eyepiece) field of the view, in which case the user preferably knows the star pattern around the prominent star, so that he may center that star rather than the many other stars that appear in the field of view. The user must know the large field, spotting scope field, and main scope field for at least two stars that are likely to be visible, but in practice must know several stars (in case Spica is already low and hidden by fog or a marine layer, or Vega is behind a mountain, or Arcturus is hidden by a neighbor's tree). If the user succeeds in the summer time, he must learn a new set of stars come fall, spring or winter, when Vega, Arcturus, Spica are no longer visible, but Betelguese, Sirius, and Aldebaran are visible. Thus, familiarity with the night sky is required for the successful use of this system, but many people see that as a difficult task, and it is precisely the task that is supposedly obviated by the system.
Locating stars is much easier with our own SkyScout™ device, and application of the technology disclosed in our U.S. Pat. No. 6,366,212 to telescopes will greatly facilitate alignment and subsequent locating and identification of celestial objects. To calibrate the SkyScout™ device, or a telescope fitted with the device, the user simply turns the device on.
Both systems discussed above benefit from the retrieval or entry of accurate time and position data. Time and position data can be obtained through GPS or other electronic positioning system, or it can be manually entered. Each has its advantages and disadvantages. GPS positioning is accurate and easy for the user, but requires additional hardware and software adding substantial development and manufacturing cost. Manual entry requires little additional hardware, but is tedious for the user and mistakes in entry such as entry of the incorrect time or forgetting daylight savings time, result in inaccuracy that may not be apparent to a user. For example, near the celestial equator, one minute of error in time will translate into 0.5 degree of error in the sky, a thumb's width at an arm's length. Errors in manual entry are likely to leave the user frustrated by a device that appears to be broken, if they are sharp enough to know the device is pointing to the wrong star. An equally problematic issue is not knowing your precise location when you are in a rural area without a zip code such as a wilderness area.
What is needed is a device for locating and identifying celestial objects that does not include expensive and complicated GPS components and does not require manual entry of accurate time and or location information to calibrate the device.